JP6551355B2 - Two-component developer and manufacturing method thereof - Google Patents

Description

  The present invention relates to a two-component developer and a method for producing the same.

  For example, a two-component developer comprising a toner and a carrier that charges the toner by friction is known (see, for example, Patent Document 1). The toner described in Patent Document 1 includes a plurality of toner particles each including toner base particles and a plurality of external additive particles attached to the surface of each toner base particle. The carrier described in Patent Document 1 includes a plurality of carrier particles having a carrier core and a carrier coat layer covering the surface of the carrier core. Further, in the two-component developer described in Patent Document 1, since the triboelectric charging order is the same between the surface of the toner base particle and the carrier coat layer, the toner base particle on the surface of the carrier particle is used even for long time use. Can prevent the adhesion of

JP-A-8-328294

  However, Patent Document 1 does not take any measures against the adhesion or burying of external additive particles on the surface of carrier particles. Therefore, in the two-component developer described in Patent Document 1, the external additive particles may adhere to or be buried in the surface of the carrier particles after prolonged use. Here, the external additive particles adhere to the surface of the toner base particles. Therefore, due to the adhesion or burying of the external additive particles to the surface of the carrier particles, the toner base particles may adhere to or bury on the surface of the carrier particles together with the external additive particles. As described above, in the two-component developer described in Patent Document 1, adhesion or embedding of toner particles on the surface of carrier particles may not be sufficiently prevented.

  When the toner particles adhere to the surface of the carrier particles, the toner and the carrier are hardly triboelectrically charged, which causes a decrease in the charge amount of the toner. In addition, when the toner particles are buried in the surface of the carrier particles, the toner tends to be excessively charged. Even when the charge amount of the toner is reduced, the developability of the toner is reduced even if the toner is excessively charged.

  The problem of fixing or embedding toner particles on the surface of carrier particles becomes significant when continuous printing is performed. For this reason, the decrease in the developability of the toner due to this problem becomes significant when continuous printing is performed.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a two-component developer having excellent toner developability even when continuous printing is performed. Another object of the present invention is to provide a method for producing a two-component developer having excellent toner developability even when continuous printing is performed.

  The two-component developer according to the present invention includes an electrostatic latent image developing toner and an electrostatic latent image developing carrier that charges the electrostatic latent image developing toner by friction. The electrostatic latent image developing toner contains a plurality of toner particles each having toner base particles and a plurality of external additive particles attached to the surface of the toner base particles. The electrostatic latent image developing carrier includes a plurality of carrier particles having a carrier core and a carrier coat layer covering a surface of the carrier core. The external additive particles include a plurality of first external additive particles having a number average primary particle diameter of 50 nm or more and 150 nm or less. Each of the first external additive particles and the carrier coat layer contains a first resin. The first resin is a phenol resin, an epoxy resin, or a silicone resin.

  According to the two-component developer of the present invention, a two-component developer having excellent toner developability can be provided even when continuous printing is performed.

It is a figure showing composition of a two-component developer concerning this embodiment.

  An embodiment of the present invention will be described. The evaluation results (values indicating the shape, physical properties, etc.) of the powder (more specifically, toner base particles, external additive particles, toner particles, carrier core, carrier particles, etc.) must be specified at all. For example, it is the number average of the values measured for each of the average particles by selecting a considerable number of average particles from the powder.

The number average primary particle diameter of the powder is the number average value of the circle equivalent diameter of the primary particles (diameter of a circle having the same area as the projected area of the particles) measured using a microscope if nothing is specified. . In addition, the measurement value of the volume median diameter (D ₅₀ ) of the powder is measured using a laser diffraction / scattering type particle size distribution measuring apparatus (“LA-750” manufactured by Horiba, Ltd.) unless otherwise specified. It is the value.

  The chargeability means the chargeability in frictional charging unless otherwise specified. The strength of positive charging in frictional charging or the strength of negative charging in frictional charging can be confirmed by a known charge train or the like.

  Hereinafter, “system” may be added after the compound name to generically generically refer to the compound and its derivative. When a “system” is added after the compound name to represent a polymer name, it means that the repeating unit of the polymer is derived from the compound or its derivative. Acrylic and methacrylic are sometimes collectively referred to as “(meth) acrylic”. Further, acrylonitrile and methacrylonitrile may be collectively referred to as “(meth) acrylonitrile”.

[Configuration of Two-Component Developer According to this Embodiment]
The two-component developer according to the exemplary embodiment includes an electrostatic latent image developing toner (hereinafter sometimes referred to as toner) and an electrostatic latent image developing carrier (hereinafter referred to as carrier) that charges the toner by friction. Have to do). The toner includes a plurality of toner particles each having toner mother particles and a plurality of external additive particles attached to the surfaces of the toner mother particles. The carrier includes a plurality of carrier particles having a carrier core and a carrier coat layer covering the surface of the carrier core. The external additive particles include a plurality of first external additive particles having a number average primary particle diameter of 50 nm or more and 150 nm or less. The first external additive particles and the carrier coat layer each contain a first resin. The first resin is a phenol resin, an epoxy resin, or a silicone resin. Thereby, even when continuous printing is performed, a two-component developer excellent in toner developability can be provided.

  Generally, in the case of forming an image using a two-component developer, the two-component developer is supplied to the storage portion of the developing device of the image forming apparatus. In this container, the two-component developer is stirred, or the two-component developer and the replenished toner are stirred. By this stirring, the toner and the carrier are rubbed against each other, and the toner and the carrier cause frictional charging.

  In the present embodiment, the plurality of first external additive particles adhere to the surface of the toner base particle, and the surface of the carrier core is covered with the carrier coat layer. Here, the number average primary particle diameter of the first external additive particles is 50 nm or more and 150 nm or less. Therefore, when the toner and the carrier are rubbed against each other, the first external additive particles adhering to the surface of the toner base particle and the carrier coat layer easily come into contact with each other.

  Specifically, when the number average primary particle diameter of the first external additive particles is 50 nm or more, it is possible to prevent the toner base particles from contacting the carrier coat layer when the toner and the carrier are rubbed against each other. In addition, even when the external additive particles further include external additive particles different from the first external additive particles (for example, second external additive particles described later), the number average primary of the first external additive particles If the particle diameter is 50 nm or more, the number average primary particle diameter of the first external additive particles tends to be larger than the number average primary particle diameter of the external additive particles different from the first external additive particles. . Therefore, when the toner and the carrier are rubbed against each other, external additive particles different from the first external additive particles can be prevented from coming into contact with the carrier coat layer. From the above, if the number average primary particle diameter of the first external additive particles is 50 nm or more, when the toner and the carrier are rubbed together, the first external additive particles and the carrier coat layer are easily in contact with each other.

  Further, if the number average primary particle diameter of the first external additive particles is 150 nm or less, the first external additive particles are easily fixed on the surface of the toner base particles. Therefore, even if the toner and the carrier are rubbed against each other, the first external additive particles can be prevented from being detached from the surface of the toner base particles. Therefore, when the toner and the carrier are rubbed together, the first external additive particles and the carrier coat layer are likely to come into contact with each other.

  As described above, in the present embodiment, when the toner and the carrier are rubbed together, the first external additive particles and the carrier coat layer are easily in contact with each other. Here, the first external additive particles and the carrier coat layer each contain a first resin. Therefore, since the first external additive particles and the carrier coat layer are charged to the same polarity by rubbing the toner and the carrier, the first external additive particles and the carrier coat layer are easily electrically repelled. Accordingly, it is possible to prevent the first external additive particles from adhering to and being buried in the carrier coat layer.

  The first resin contained in each of the first external additive particles and the carrier coat layer is a phenol resin, an epoxy resin, or a silicone resin. Here, since all of the phenolic resin, the epoxy resin, and the silicone resin are thermosetting resins, the first external additive particles and the carrier coat layer all contain a thermosetting resin. The thermosetting resin is relatively hard. Therefore, the hardness of each of the first external additive particles and the carrier coat layer is high. This can also prevent the first external additive particles from adhering and burying in the carrier coat layer.

  Here, the first external additive particles adhere to the surface of the toner base particles. Therefore, if the first external additive particles can be prevented from adhering to and being buried in the carrier coat layer, the toner base particles can be prevented from adhering to and being buried in the carrier coat layer together with the first external additive particles. That is, it is possible to prevent the toner particles from being attached and buried on the surface of the carrier particles. If the toner particles can be prevented from adhering to the surface of the carrier particles, the toner and the carrier are frictionally charged, so that the decrease in the charge amount of the toner can be prevented. Further, if the toner particles can be prevented from being buried in the surface of the carrier particles, it is possible to prevent the toner from being excessively charged. As described above, the toner contained in the two-component developer according to the present embodiment exhibits excellent chargeability, and thus exhibits excellent developability. For example, if an image is formed using the two-component developer according to this embodiment, an image with excellent image density can be provided. Here, that the toner exhibits good charge stability means that the toner has a sharp charge amount distribution characteristic, and the charge amount of the toner becomes a desired charge amount when the image formation is started using the toner. This means that the toner has the property of being able to be maintained, and the property of being able to maintain the charge amount of the toner at a desired charge amount when an image is continuously formed using the toner.

  As described above, in the present embodiment, the number average primary particle diameter of the first external additive particles is 50 nm or more and 150 nm or less, and each of the first external additive particles and the carrier coat layer contains the first resin. In addition, the first resin is a phenol resin, an epoxy resin, or a silicone resin, thereby preventing adhesion and burying of the toner particles on the surface of the carrier particles. Here, even when continuous printing is performed, the number average primary particle diameter of the first external additive particles is considered to be hard to change, and each material of the first external additive particles and the carrier coat layer is also considered. Is unlikely to change. Therefore, even when continuous printing is performed, it is possible to prevent toner particles from adhering to and embedding on the surface of the carrier particles. Therefore, even when continuous printing is performed, the toner contained in the two-component developer according to the present embodiment exhibits excellent chargeability and thus exhibits excellent developability.

  When the first resin is a phenol resin, an epoxy resin, or a silicone resin, the toner particles tend to be positively charged. Specifically, the phenolic resin, the epoxy resin, and the silicone resin each have negative chargeability. Therefore, when the carrier coat layer contains a phenol resin, an epoxy resin, or a silicone resin, the carrier particles are easily negatively charged. When carrier particles and toner particles that are easily charged negatively are rubbed together, the toner particles are easily charged positively. Therefore, in this embodiment, a positively chargeable toner can be provided.

  In addition, as a thermosetting resin, a melamine resin and a urea resin are mentioned separately from a phenol resin, an epoxy resin, and a silicone resin. Here, the melamine resin and the urea resin each have relatively strong positive chargeability. Therefore, when the carrier coat layer contains a melamine resin or a urea resin, the carrier particles tend to be positively charged. When the carrier particles that tend to be positively charged and the toner particles are rubbed together, it becomes difficult to positively charge the toner particles. Therefore, when providing a positively chargeable toner, it is preferable to use a phenol resin, an epoxy resin, or a silicone resin as the first resin rather than a melamine resin or a urea resin.

  The first resin contained in the first external additive particles and the first resin contained in the carrier coat layer preferably have the same chemical structure of the monomers, and the polymerization degrees of the monomers are the same. preferable. Thereby, in the first resin contained in the first external additive particle and the first resin contained in the carrier coat layer, the chemical structural formulas become the same. Therefore, when the toner and the carrier are rubbed together, the electric repulsion between the first external additive particles and the carrier coat layer is more likely to occur. Therefore, the first external additive particles can be further prevented from adhering to and being buried in the carrier coat layer, and therefore, the toner base particles can be further prevented from adhering and being buried in the carrier coat layer together with the first external additive particles. . That is, it is possible to further prevent the toner particles from being attached and buried in the carrier coat layer. Therefore, even when continuous printing is performed, the charge stability of the toner is further improved, and the developability of the toner is further improved.

  When the first resin contains a repeating unit derived from a curing agent, the curing agent having the same chemical structure as the first resin contained in the first external additive particle and the first resin contained in the carrier coat layer It is preferable that the repeating unit derived from is included. Thereby, in the first resin contained in the first external additive particle and the first resin contained in the carrier coat layer, the chemical structural formulas become the same. Therefore, it is possible to further prevent the first external additive particles from adhering to and burying in the carrier coat layer. In addition, when the first resin includes a repeating unit derived from a curing agent, the hardness of the first resin is further increased. Therefore, the hardness of each of the first external additive particles and the carrier coat layer is further increased. This also can further prevent adhesion and burial of the first external additive particles to the carrier coat layer. For these reasons, it is possible to further prevent the toner base particles from adhering to and buried in the carrier coat layer together with the first external additive particles. That is, it is possible to further prevent the toner particles from being attached and buried in the carrier coat layer. Therefore, even when continuous printing is performed, the charge stability of the toner is further improved, and the developability of the toner is further improved.

  Among the thermosetting resins, the first resin is preferably a silicone resin. This facilitates the production of the first external additive particles and the formation of the carrier coat layer, which facilitates the production of the two-component developer.

  Preferably, the content of the first external additive particles in the toner particles is 0.500 parts by mass or more and 2.70 parts by mass or less with respect to 100 parts by mass of the toner base particles. When the content of the first external additive particles in the toner particles is 0.500 parts by mass or more with respect to 100 parts by mass of the toner base particles, the first external additive particles easily function as a spacer. Specifically, when the toner and the carrier are rubbed against each other, the carrier base particles can be further prevented from contacting the carrier coat layer, and the contact of the first external additive particles to the carrier coat layer can be easily secured. Here, the resin contained in the first external additive particles and the resin contained in the carrier coat layer are both the first resin, and the first resin is a phenol resin, an epoxy resin, or a silicone resin. For this reason, the above-described effect is easily obtained. That is, even when continuous printing is performed, the effect of exhibiting excellent toner developability is easily obtained. If the content of the first external additive particles in the toner particles is 2.70 parts by mass or less with respect to 100 parts by mass of the toner base particles, the external surface of the toner base particles is different from the first external additive particles. It is possible to secure a space for externally adding additive particles (for example, external additive particles that have been subjected to a positive charging process) to the surface of the toner base particles. Thereby, the toner can be positively and sufficiently charged. More preferably, the content of the first external additive particles in the toner particles is 1.00 parts by mass to 1.80 parts by mass with respect to 100 parts by mass of the toner base particles. The content of the first external additive particles in the toner particles can be determined, for example, by fluorescent X-ray analysis.

  The external additive particles preferably include a plurality of silica particles (hereinafter referred to as second external additive particles) which have been subjected to a positive charging treatment, separately from the first external additive particles. Thereby, the toner can be positively and sufficiently charged. Further, the number average primary particle diameter of the second external additive particles is preferably smaller than the number average primary particle diameter of the first external additive particles. Therefore, when the toner and the carrier are rubbed together, the first external additive particles are preferentially in contact with the surface of the carrier particles rather than the second external additive particles. Here, the resin contained in the first external additive particles and the resin contained in the carrier coat layer are both the first resin, and the first resin is a phenol resin, an epoxy resin, or a silicone resin. Therefore, even when the external additive particles contain a plurality of second external additive particles in addition to the first external additive particles, the above-described effects, that is, even when continuous printing is performed The effect of being excellent in developability can be obtained.

  The number average primary particle diameter of the second external additive particles is preferably 0.7 times or less the number average primary particle diameter of the first external additive particles, and more preferably the number average primary of the first external additive particles. The particle diameter is 0.1 times or more and 0.7 times or less, and more preferably 0.1 times or more and 0.3 times or less the number average primary particle diameter of the first external additive particles.

The silica particles subjected to the positive charging treatment mean that OH is substituted with a functional group having a higher positive charge than OH in at least one of the silanol groups present on the surface of the silica particles. Examples of the functional group having a higher positive charge than OH include an amino group (—NH ₂ group). The content of the second external additive particles in the toner particles is preferably 1.30 parts by mass to 1.70 parts by mass with respect to 100 parts by mass of the toner base particles.

  Preferably, the thickness of the carrier coat layer is 10 nm or more. This makes it easy to increase the hardness of the carrier coat layer to the same degree as the hardness of the first external additive particles. Therefore, the first external additive particles can be further prevented from adhering to and being buried in the carrier coat layer, and therefore, the toner base particles can be further prevented from adhering and being buried in the carrier coat layer together with the first external additive particles. . That is, it is possible to further prevent the toner particles from being attached and buried in the carrier coat layer. Therefore, even when continuous printing is performed, the charge stability of the toner is further improved, so that the developability of the toner is further improved. More preferably, the thickness of the carrier coat layer is 10 nm or more and 100 nm or less. The thickness of the carrier coat layer means the dimension of the carrier coat layer in the direction perpendicular to the surface of the carrier core, and can be measured by the method described in Examples described later or a method analogous thereto.

  The coverage of the carrier coat layer on the surface of the carrier core is preferably 80% or more, more preferably 90% or more, and even more preferably 100%. If the coverage of the carrier coat layer on the surface of the carrier core is high, the first external additive particles are in contact with the part of the surface of the carrier particles exposed from the carrier coat layer (hereinafter referred to as the exposed surface of the carrier particles). Can be prevented. Therefore, it is possible to prevent the toner base particles from being attached and buried on the exposed surfaces of the carrier particles together with the first external additive particles. That is, the toner particles can be prevented from adhering to and being buried in the exposed surfaces of the carrier particles. Therefore, even when continuous printing is performed, the charge stability of the toner is further improved, and the developability of the toner is further improved. The coating state of the carrier coat layer on the surface of the carrier core can be confirmed by the method described in the examples below or a method according thereto.

  Hereinafter, an example of the configuration of the two-component developer according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram showing a configuration of a two-component developer according to this embodiment.

  The two-component developer 100 according to this embodiment includes a toner and a carrier that charges the toner by friction. The toner includes a plurality of toner particles 10 shown in FIG. The toner particles 10 each have toner base particles 11 and a plurality of external additive particles 13 attached to the surfaces of the toner base particles 11 respectively. The plurality of external additive particles 13 include a plurality of first external additive particles 15 and a plurality of second external additive particles 17. The number average primary particle diameter of the first external additive particles 15 is not less than 50 nm and not more than 150 nm. The second external additive particles 17 are silica particles that have a number average primary particle diameter smaller than the number average primary particle diameter of the first external additive particles 15 and are positively charged.

  The carrier includes a plurality of carrier particles 20 shown in FIG. The carrier particles 20 each have a carrier core 21 and a carrier coat layer 25 covering the surface of the carrier core 21.

  The first external additive particles 15 and the carrier coat layer 25 are each composed of a first resin. The first resin is a phenol resin, an epoxy resin, or a silicone resin. The example of the configuration of the two-component developer according to the present embodiment has been described above with reference to FIG. Hereinafter, a preferred production method of the two-component developer according to the present embodiment will be described.

[Preferred production method of two-component developer according to this embodiment]
A preferable manufacturing method of the two-component developer according to the present embodiment includes a toner manufacturing process, a carrier manufacturing process, and a mixing process. The toner production process preferably includes a production process of the first external additive particles. The carrier manufacturing process preferably includes a carrier coat layer forming process. The step of forming the carrier coat layer preferably includes the step of providing a film containing the first solution on the surface of the carrier core. The first solution preferably includes first external additive particles and a first solvent that dissolves the first external additive particles.

  If a solution containing a first external additive particle and a first solvent capable of dissolving the first external additive particle is used as the first solution, the first external additive particle is contained in the manufactured two-component developer. The first resin to be added and the first resin contained in the carrier coat layer have the same chemical structural formula. Therefore, when the toner and the carrier are rubbed against each other, electrical repulsion between the first external additive particles and the carrier coat layer is more likely to occur. Therefore, the first external additive particles can be further prevented from adhering to and being buried in the carrier coat layer, and therefore, the toner base particles can be further prevented from adhering and being buried in the carrier coat layer together with the first external additive particles. . That is, it is possible to further prevent the toner particles from being attached and buried in the carrier coat layer. As a result, even in the case of continuous printing, the charge stability of the toner is further improved, and the developability of the toner is further improved. Hereinafter, a preferred method for producing the two-component developer according to the exemplary embodiment will be described in the order of steps.

<Toner preparation process>
The toner preparation step preferably includes a toner mother particle production step, an external additive production step, and an external addition step. In addition, in order to manufacture a toner efficiently, it is preferable to manufacture many toner particles simultaneously. The toner particles produced simultaneously are considered to have substantially the same configuration.

(Manufacturing process of toner base particles)
When the toner base particles have a toner core and a shell layer, the toner base particles are preferably manufactured by sequentially performing the toner core manufacturing step and the shell layer forming step. When the toner base particles do not have a shell layer, it is preferable to manufacture the toner base particles without performing the shell layer forming step after the toner core manufacturing step.

(Manufacturing process of toner core)
It is preferable to produce the toner core by a known aggregation method or a known grinding method. Thereby, the toner core can be easily manufactured.

(Shell layer formation process)
For example, the shell layer can be formed using any of in-situ polymerization method, in-liquid curing coating method, and coacervation method.

(External additive preparation process)
The step of preparing the external additive preferably includes the step of producing the first external additive particle, and more preferably further includes the step of producing the second external additive particle.

(Process for producing first external additive particles)
It is preferable to produce the first external additive particles by the following method. First, a monomer or a reaction intermediate is polymerized to synthesize a first resin. Examples of the reaction intermediate include a prepolymer. The first resin may be synthesized by polymerizing the monomer or the reaction intermediate in the presence of a crosslinking agent. Next, the synthesized first resin is formed into particles having a desired particle diameter. Polymerization and molding may be performed simultaneously. Thus, the first external additive particles are obtained. In order to efficiently produce the first external additive particles, it is preferable to produce a large number of first external additive particles simultaneously. The first external additive particles produced simultaneously are considered to have substantially the same configuration.

  Since the hardness of the first resin can be adjusted by controlling the polymerization conditions of the first resin, the hardness of each of the first external additive particles and the carrier coat layer containing the first resin can be adjusted. Examples of the polymerization conditions for the first resin include the polymerization time of the monomer or reaction intermediate (hereinafter referred to as polymerization time), or the polymerization temperature of the monomer or reaction intermediate (hereinafter referred to as polymerization temperature). . In general, a preferred polymerization method of the monomer or reaction intermediate is selected depending on the material of the monomer or reaction intermediate. Then, depending on the preferred polymerization method of the monomer or reaction intermediate, the preferred polymerization time and the preferred polymerization temperature are determined. Thus, the preferred polymerization time and the preferred polymerization temperature each depend on the monomer or reaction intermediate material. Therefore, although it can not generally be said, 30 minutes or more and 48 hours or less are mentioned as a preferable example of superposition | polymerization time, 1 hours or more and 24 hours or less are mentioned as a more preferable example of superposition | polymerization time. Although it can not generally be said, a preferable example of the polymerization temperature includes 60 ° C. or more and 110 ° C. or less, and a more preferable example of the polymerization temperature includes 65 ° C. or more and 105 ° C. or less.

(Production process of second external additive particles)
The second external additive particles are preferably produced by the following method. First, silica particles are produced by a known sol-gel method. The produced silica particles are subjected to a hydrophobization treatment and a positive charging treatment. In the hydrophobization treatment, it is preferable to treat the surface of the silica particles using a known hydrophobizing agent. In the positive charging treatment, it is preferable to treat the surface of the silica particles with a known positive charge imparting agent. In order to efficiently produce the second external additive particles, it is preferable to produce a large number of second external additive particles simultaneously. The second external additive particles manufactured simultaneously are considered to have substantially the same configuration as each other.

(External addition process)
The toner base particles and the external additive are mixed using a mixer (for example, an FM mixer manufactured by Nippon Coke Kogyo Co., Ltd.). As a result, the external additive is physically bonded to the surface of the toner base particles. In this way, a toner containing a large number of toner particles is obtained.

<Career preparation process>
The carrier preparation step preferably includes a carrier core manufacturing step and a carrier coat layer forming step. In addition, in order to manufacture a carrier effectively, it is preferable to manufacture many carrier particles simultaneously. The carrier particles manufactured at the same time are considered to have substantially the same configuration.

(Carrier core manufacturing process)
It is preferable to produce a carrier core by a method known as a method for producing a carrier core.

(Formation process of carrier coat layer)
Examples of a method of forming a carrier coat layer on the surface of the carrier core include a dip coat method, a spray coat method, a spin coat method, a roller coat method, a bead coat method, a blade coat method, or a bar coat method. Among these, when a carrier coat layer is formed on the surface of the carrier core by a spray coat method, a carrier coat layer having a thickness of 10 nm or more can be relatively easily formed.

  Specifically, first, a first solution is prepared. The prepared first solution preferably contains at least one of a first resin, a monomer capable of producing a first resin by polymerization reaction, and a reaction intermediate capable of producing a first resin by polymerization reaction. More preferably, the first solution contains first external additive particles and a first solvent for dissolving the first external additive particles. Examples of the first solvent include methyl ethyl ketone.

  Next, the prepared first solution is supplied to the surface of the carrier core. Thereby, the 1st film | membrane containing a 1st solution is provided in the surface of a carrier core.

  Subsequently, heat is applied to the carrier core provided with the first film on the surface. Thereby, the liquid component contained in the first film is vaporized. In addition, when the first film contains a monomer or a reaction intermediate, the monomer or the reaction intermediate is polymerized. As a result, a carrier coat layer containing the first resin is formed on the surface of the carrier core. In this way, a carrier containing a large number of carrier particles is obtained.

<Mixing process>
The toner and the carrier are mixed and stirred. At this time, the toner particles are preferably added in an amount of 1 to 20 parts by mass, more preferably 3 to 15 parts by mass, with respect to 100 parts by mass of the carrier particles. In addition, the toner particles and the carrier particles can be mixed and stirred using a mixer (for example, a ball mill, a Nauter mixer, or a rocking mixer). Thus, the two-component developer according to the present embodiment is obtained.

[Examples of toner base particles, external additives, and carrier particle materials]
Hereinafter, first, the first external additive particles and the first resin contained in the carrier coat layer will be specifically described. Next, each material of toner base particles, second external additive particles, and carrier core will be described.

<First resin>
The first resin is a phenol resin, an epoxy resin, or a silicone resin.

(Phenolic resin)
The phenol resin is obtained by reacting phenols with formaldehyde and has a three-dimensional network structure. The phenol resin is preferably, for example, various novolak-type phenol resins, polyfunctional phenol resins, or alicyclic phenol resins. As a phenol resin, these can be used individually or in mixture of 2 or more types.

(Epoxy resin)
The epoxy resin is synthesized by reacting an epoxy compound having an epoxy group (preferably an alicyclic epoxy compound) and its curing agent to cross-link three-dimensionally. Therefore, the epoxy resin has a three-dimensional network structure like the phenol resin.

  Examples of the epoxy resin include glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, brominated bisphenol A type epoxy resin, polyfunctional type epoxy resin, various novolac type epoxy resins, It is preferable that it is an alicyclic epoxy resin, a dicyclopentadiene type epoxy resin, or a biphenyl type epoxy resin. As an epoxy resin, these can be used individually or in mixture of 2 or more types.

(Silicone resin)
The silicone-based resin has a siloxane bond “Si—O—Si” as a main chain, an organic group as a side chain, and a three-dimensional network structure. The methyl silicone resin has only a methyl group as a side chain organic group. The methyl phenyl silicone resin has a methyl group and a phenyl group as an organic group of a side chain. The silicone resin has, for example, a structure represented by the following formula (1-1) or the following formula (1-2). N ₁₁ , n ₂₁ , and n ₂₂ in formula (1-1) and formula (1-2) each independently represent the number of repeating units (arbitrary number). In order for the silicone resin to have excellent durability, the main chains (siloxane bonds: Si—O—Si) of the silicone resin are preferably three-dimensionally connected.

In formula (1-1), R ₁₁ represents an organic group (more specifically, a methyl group or a phenyl group). R ₁₂ represents a hydrogen atom or an organic group (more specifically, a methyl group or a phenyl group). R ₁₁ and R ₁₂ may be identical to or different from each other. Y ₁₁ represents the first terminal part, and Y ₁₂ represents the second terminal part. For example, an organosiloxy group (more specifically, a trimethylsiloxy group) is attached to the first terminal portion. For example, an organosilyl group (more specifically, a trimethylsilyl group) is attached to the second terminal portion.

In formula (1-2), R ₂₁ , R ₂₂ and R ₂₃ each independently represents an organic group (more specifically, a methyl group or a phenyl group). R ₂₄ represents a hydrogen atom or an organic group (more specifically, a methyl group or a phenyl group). Y ₂₁ represents a first end, and Y ₂₂ represents a second end. For example, an organosiloxy group (more specifically, a trimethylsiloxy group) is attached to the first terminal portion. For example, an organosilyl group (more specifically, a trimethylsilyl group) is attached to the second terminal portion.

<Toner base particles>
When the toner base particles are capsule toners, the toner base particles include the following toner core and the following shell layer. When the toner base particles are non-capsule toner, the toner base particles correspond to the following toner core.

(Toner core)
The toner core contains a binder resin. The toner core may further contain at least one of a colorant, a release agent, and a charge control agent.

(Toner core: Binder resin)
In the toner core, generally, the binder resin occupies most (for example, 85% by mass or more) of the components. Therefore, it is considered that the properties of the binder resin greatly affect the properties of the entire toner core.

  Further, by combining and using a plurality of resins as the binder resin, the properties of the binder resin (specifically, the hydroxyl value, the acid value, the glass transition point, or the softening point) can be adjusted. For example, when the binder resin has an ester group, a hydroxyl group, an ether group, an acid group, or a methyl group, the toner core tends to be anionic. When the binder resin has an amino group or an amide group, the toner core tends to be cationic. In order for the binder resin to have strong anionic property, it is preferable that at least one of the acid value and the hydroxyl value of the binder resin is 10 mg KOH / g or more.

  The toner core preferably contains a thermoplastic resin. As a thermoplastic resin, polyester resin, a styrene resin, acrylic acid resin, an olefin resin, a vinyl resin, a polyamide resin, or a urethane resin can be used, for example. As acrylic resin, acrylic acid ester polymer or methacrylic acid ester polymer can be used, for example. As the olefin resin, for example, a polyethylene resin or a polypropylene resin can be used. As a vinyl resin, a vinyl chloride resin, polyvinyl alcohol, vinyl ether resin, or N-vinyl resin can be used, for example. A copolymer of each of these resins, that is, a copolymer in which an arbitrary repeating unit is introduced into the resin, can also be used as the thermoplastic resin constituting the toner particles. For example, a styrene-acrylic acid resin or a styrene-butadiene resin can also be used as a thermoplastic resin constituting a toner core. Hereinafter, a polyester resin which is an example of the binder resin will be described in detail.

  The polyester resin is obtained by polycondensing one or more alcohols and one or more carboxylic acids. As an alcohol for synthesizing a polyester resin, for example, a dihydric alcohol or a trivalent or higher alcohol shown below can be used. As the dihydric alcohol, for example, diols or bisphenols can be used. As the carboxylic acid for synthesizing the polyester resin, for example, the following divalent carboxylic acids or trivalent or higher carboxylic acids can be used.

  As the diols, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 2-butene-1,4-diol 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, or polytetramethylene glycol.

  Examples of bisphenols include bisphenol A, hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, or bisphenol A propylene oxide adduct.

  Examples of the trivalent or higher alcohol include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-Pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane or 1,3,5-trihydroxyl Methylbenzene is mentioned.

  Examples of the divalent carboxylic acid include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, succinic acid. Acid, alkyl succinic acid (more specifically, n-butyl succinic acid, isobutyl succinic acid, n-octyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, etc.), or alkenyl succinic acid (more specifically, And n-butenylsuccinic acid, isobutenylsuccinic acid, n-octenylsuccinic acid, n-dodecenylsuccinic acid, or isododecenylsuccinic acid, etc.).

  Examples of trivalent or higher carboxylic acids include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,3 4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, or empole trimer acid.

(Toner Core: Colorant)
As the colorant, known pigments or dyes may be used in accordance with the color of the toner. In order to form a high-quality image using toner, the amount of the colorant is preferably 1.00 parts by mass or more and 20.0 parts by mass or less with respect to 100 parts by mass of the binder resin.

  The toner core may contain a black colorant. An example of a black colorant is carbon black. The black colorant may be a colorant toned to black using a yellow colorant, a magenta colorant, and a cyan colorant.

  The toner core may contain color colorants such as yellow colorants, magenta colorants, or cyan colorants.

  As the yellow colorant, for example, one or more compounds selected from the group consisting of condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and arylamide compounds can be used. Examples of the yellow colorant include C.I. I. Pigment Yellow (3, 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155 168, 174, 175, 176, 180, 181, 191 or 194), Naphthol Yellow S, Hansa Yellow G or C.I. I. Bat yellow can be used.

  The magenta colorant is selected, for example, from the group consisting of condensation azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. One or more compounds can be used. Examples of the magenta colorant include C.I. I. Pigment red (2, 3, 5, 6, 7, 19, 19, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 150, 166, 169, 177 184, 185, 202, 206, 220, 221, or 254).

  As the cyan colorant, for example, one or more compounds selected from the group consisting of a copper phthalocyanine compound, an anthraquinone compound, and a basic dye lake compound can be used. Examples of cyan colorants include C.I. I. Pigment blue (1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62 or 66), phthalocyanine blue, C.I. I. Bat blue or C.I. I. Acid Blue can be used.

(Toner core: mold release agent)
The release agent is used, for example, for the purpose of improving the fixing property or the offset resistance of the toner. In order to increase the anionicity of the toner core, it is preferable to produce the toner core using an anionic wax. In order to improve the fixing property or offset resistance of the toner, the amount of the release agent is preferably 1.00 parts by mass or more and 30.0 parts by mass or less with respect to 100 parts by mass of the binder resin.

  Examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, or aliphatic hydrocarbon wax such as Fischer-Tropsch wax; oxidized polyethylene wax or a block thereof Oxides of aliphatic hydrocarbon waxes such as copolymers; plant waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax, or rice wax; animal properties such as beeswax, lanolin, or whale wax Waxes; mineral waxes such as ozokerite, ceresin, or petrolatum; waxes based on fatty acid esters such as montanate ester wax or castor wax; fats such as deoxidized carnauba wax The wax portion of the ester or the whole was deoxygenated be used. One type of release agent may be used alone, or multiple types of release agents may be used in combination.

  A compatibilizer may be added to the toner core in order to improve the compatibility between the binder resin and the release agent.

(Toner core: charge control agent)
The charge control agent is used, for example, for the purpose of improving the charge stability or charge rise characteristics of the toner. The charge rising characteristic of the toner is an index as to whether or not the toner can be charged to a predetermined charge level in a short time.

  By including a negatively chargeable charge control agent in the toner core, the anionic property of the toner core can be enhanced. Further, the cationic property of the toner core can be increased by including a positively chargeable charge control agent in the toner core. However, if sufficient chargeability is ensured in the toner, it is not necessary to include a charge control agent in the toner core.

(Shell layer)
The shell layer preferably contains a thermoplastic resin. As the thermoplastic resin contained in the shell layer, for example, the thermoplastic resin described in the above (toner core: binder resin) can be used. Preferably, the shell layer contains a copolymer of one or more styrene monomers and one or more acrylic monomers. Thereby, the charging stability of the toner can be further improved. As the styrene monomer, for example, styrene can be used. As the acrylic monomer, for example, an acrylic ester can be used.

  The shell layer may further contain a thermosetting resin. Examples of the thermosetting resin contained in the shell layer include an aminoaldehyde resin, a polyimide resin, or a xylene-based resin. The amino aldehyde resin is a resin formed by condensation polymerization of a compound having an amino group and an aldehyde. Here, as the aldehyde, for example, formaldehyde can be used. Examples of the aminoaldehyde resin include melamine resins, urea resins, sulfonamide resins, glyoxal resins, guanamine resins, or aniline resins. As the polyimide resin, for example, a maleimide polymer or a bismaleimide polymer can be used.

<Second external additive particles>
The second external additive particles are preferably silica particles that have been subjected to a positive charging treatment, and more preferably silica particles that have been subjected to a hydrophobic treatment and a positive charging treatment. The second external additive particles are preferably, for example, hydrophilic silica particles or hydrophilic fumed silica particles.

  The external additive may further include external additive particles (hereinafter, referred to as third external additive particles) different from the first external additive particles and the second external additive particles. The third external additive particles are preferably particles containing, for example, alumina, zirconia, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, or barium titanate.

<Carrier core>
The carrier core included in the carrier particles is preferably made of magnetic particles. The magnetic particles constituting the carrier core and the magnetic particles contained in the resin carrier include, for example, particles composed of iron, oxidized iron, reduced iron, magnetite, copper, silicon steel, ferrite, nickel, or cobalt; Examples thereof include particles made of an alloy of manganese, zinc or aluminum; particles made of an alloy of iron and nickel or cobalt; particles made of ceramics; or particles made of a high dielectric constant substance. Examples of ceramics contained in particles made of ceramics include titanium oxide, aluminum oxide, copper oxide, magnesium oxide, lead oxide, zirconium oxide, silicon carbide, magnesium titanate, barium titanate, lithium titanate, lead titanate, Examples include lead zirconate or lithium niobate. Examples of the high dielectric constant material contained in the particles made of the high dielectric constant substance include ammonium dihydrogen phosphate, potassium dihydrogen phosphate, and Rochelle salt.

  Examples of the present invention will be described. Table 1 shows the two-component developers D-1 to D-16 according to the examples or comparative examples. Table 2 shows the configuration of the external additive particles (hereinafter referred to as resin fine particles) made of the resin used in the examples or comparative examples. In Table 2, the particle size means the number average primary particle size. Table 3 shows the configuration of the carrier coat layer used in Examples or Comparative Examples.

  In the following, first, a method of producing resin fine particles A to I, a method of measuring the number average primary particle diameter of resin fine particles A to I, a method of producing toners T-1 to T-9, and carriers C-1 to C-7. The manufacturing method, the method of measuring the thickness of the carrier coat layer, and the method of confirming the covering state of the carrier coat layer will be described in order. Next, the production method, evaluation method, and evaluation result of the two-component developers D-1 to D-16 will be described in order. In addition, in the evaluation which an error produces, the measurement value of a considerable number which an error becomes small enough was obtained, and the arithmetic mean of the obtained measurement value was made into the evaluation value.

[Production method of resin fine particles]
(Method of producing resin fine particles A to E)
In a three-necked flask equipped with a stirrer, a thermometer and a reflux condenser, 1000 parts by mass of pure water, 100.0 parts by mass of resorcinol and 0.1500 parts by mass of sodium carbonate were placed. The contents of the three-necked flask were stirred to completely dissolve resorcinol and sodium carbonate in pure water. To the three-necked flask, 147.0 parts by mass of an aqueous formaldehyde solution (concentration: 37% by mass) was further added, and the contents of the three-necked flask were stirred. Thereafter, the three-necked flask was placed in a shield case equipped with a multi-mode microwave irradiation device. Here, the shield case was grounded. The temperature in the shield case was kept at 100 ° C., and microwaves (power: 600 W) with a frequency of 2450 MHz were irradiated from a multimode microwave irradiator into a three-necked flask for 30 minutes under reflux conditions. Thereby, the contents of the three-necked flask reacted. Thereafter, the contents of the three-necked flask were separated into liquid and solid using a centrifuge. The obtained solid was dried and then crushed. In this way, a powder containing a plurality of fine particles made of a phenol resin was obtained.

  The obtained powder was classified using a classifier (wind classifier using Coanda effect: “Elbow jet EJ-LABO type” manufactured by Nittetsu Mining Co., Ltd.). At this time, at least one of the air volume and the edge angle of the classification edge in the classifier was changed, and the obtained powder was divided into five groups having different particle diameters. Thereafter, each of the five types of powders divided into groups was sieved to remove aggregates from each of the five types of powders. In this manner, five types of powders containing a plurality of each of the resin fine particles A to E were obtained.

(Method for producing resin fine particle F)
In a reaction vessel equipped with a stirring rod and a thermometer, 190 parts by mass of bisphenol A diglycidyl ether ("jER (registered trademark) 828" manufactured by Mitsubishi Chemical Co., Ltd.) and 10.0 parts by mass of organically treated clay (Zud Chemie) “Nanofil 948” manufactured by Catalyst Co., Ltd., content: inorganic clay intercalated with distearyldimethylammonium chloride) was added. The temperature in the reaction vessel was raised to 75 ° C. The contents of the reaction vessel were stirred for 24 hours while keeping the temperature in the reaction vessel at 75 ° C. Thereby, bisphenol A diglycidyl ether and the organically treated clay were uniformly mixed, and an epoxy resin was obtained.

  The temperature in the reaction vessel was lowered to room temperature. In a reaction vessel, 27.0 parts by mass of a polyethylene oxide adduct of styrenated cumylphenol (“Ionette LD-7BE-2” manufactured by Sanyo Chemical Industries, Ltd.) and 61.0 parts by mass of an aliphatic diamine (BASF) Company "Lalomin C-260") was added to dissolve them uniformly. The liquid thus obtained was used as an oil phase. Then, water was dripped at the reaction container (oil phase), stirring the contents of the reaction container. The color of the contents of the reaction vessel turned to milky white (emulsification) when the amount dropped of water to the reaction vessel reached 45.0 parts by mass. Thereafter, 656 parts by mass of water was further added dropwise to obtain a first suspension. The first suspension was heated to raise the temperature in the reaction vessel to 75 ° C., and the temperature in the reaction vessel was kept at 75 ° C. for 5 hours. Thereafter, the temperature in the reaction vessel was raised to 95 ° C., and the temperature in the reaction vessel was kept at 95 ° C. for 24 hours. While the temperature in the reaction vessel was maintained at 95 ° C., the contents of the reaction vessel reacted and the obtained product was aged. A second suspension was thus obtained. In the second suspension, fine particles made of an epoxy resin were dispersed in water. Resin fine particles (fine particles made of epoxy resin) were taken out from the second suspension by filtration. The extracted resin fine particles were dried with a circulating dryer (air temperature: 40 ° C.). Thereafter, the particle size of the resin fine particles was made uniform using an air classifier, and then the resin fine particles were sieved using a sieve of 2400 mesh (mesh 5 μm). In this way, a powder containing a plurality of resin fine particles F was obtained.

(Method for producing resin fine particle G)
In a reaction vessel equipped with a thermometer, a refluxer and a stirrer, 108 parts by mass of ion exchange water (electrical conductivity: 0.05 mS / m) and hydrochloric acid were added. In this way, a solution having a hydrochloric acid concentration of 5 × 10 ^-5 N was obtained. While maintaining the temperature of this solution at 20 ° C., 0.610 parts by mass of tetramethoxysilane, 3.40 parts by mass of methyltrimethoxysilane, and 3.00 parts by mass of dimethyldimethoxysilane are dropped into the reaction vessel. did. The dropped alkoxysilane had a molar ratio of tetramethoxysilane: methyltrimethoxysilane: dimethyldimethoxysilane = 0.16: 1: 1. The contents of the reaction vessel were stirred for 4 hours (rotational speed: 50 rpm). While stirring the contents of the reaction vessel, a hydrolysis reaction occurred in the reaction vessel. In this way, a silanol solution was obtained.

  The silanol solution was stirred while maintaining the temperature of the resulting silanol solution at 5 ° C. (rotation speed: 50 rpm). Thereafter, an aqueous ammonia solution (concentration: 1% by mass) was dropped into the silanol solution so that the amount of ammonia added was 0.272 parts by mass. Thereafter, the silanol solution was stirred for 4 hours. In this way, fine particles made of a silicone resin were obtained. The obtained fine particles (fine particles made of silicone resin) were dried. Thereafter, the particle size of the fine particles was made uniform using an air classifier, and then the fine particles were sieved using a 2400 mesh (opening 5 μm) sieve. Thus, a powder containing a plurality of resin fine particles G was obtained.

(Method for producing resin fine particles H)
In a reaction flask equipped with a stirrer, a reflux condenser, and a thermometer, 280 parts by mass of water-soluble methylol melamine (“Nikaresin (registered trademark) S-260” manufactured by Nippon Carbide Industries, Ltd.), 740 parts by mass of water, 1.40 parts by mass of ammonia water (concentration: 25% by mass) was added. At this time, the pH of the contents of the reaction flask was 8. While stirring the contents of the reaction flask, the temperature in the reaction flask was raised to 70 ° C., and the temperature in the reaction flask was kept at 70 ° C. for 30 minutes. In this way, an aqueous solution of melamine resin was obtained.

  17.0 parts by mass of PTSA (p-toluenesulfonic acid) aqueous solution (acid catalyst, concentration: 18% by mass) and 1.80 parts by mass of DBSA in an aqueous solution while keeping the temperature of the aqueous solution of the melamine resin at 70 ° C. An aqueous solution of (dodecylbenzenesulfonic acid) (acid catalyst, concentration: 10% by mass) was added. For PTSA and DBSA added, PTSA: DBSA = 97: 3 (molar ratio) and PTSA: DBSA = 97: 3 (proton donating ratio). The pH of the obtained aqueous solution was adjusted to 5. Thereafter, the aqueous solution was micronized using a spray dryer ("FOC-25" manufactured by Ogawara Kakohki Co., Ltd.) to obtain fine particles of melamine resin. The obtained resin fine particles (fine particles made of melamine resin) were heated at 100 ° C. for 5 hours to dry the resin fine particles. Thereafter, the particle size of the resin fine particles was made uniform using an air classifier, and then the resin fine particles were sieved using a sieve of 2400 mesh (mesh 5 μm). In this way, a powder containing a plurality of resin fine particles H was obtained.

(Method for producing resin fine particle I)
In a separable flask (volume: 2 L) equipped with a stirrer, a dropping funnel, a nitrogen introduction tube, and a reflux condenser, 820 parts by mass of ion-exchanged water was added. While introducing nitrogen into the separable flask and stirring the contents of the separable flask, the temperature in the separable flask was raised to 80 ° C. After maintaining the temperature in the separable flask at 80 ° C. for 30 minutes, 0.700 parts by mass of ammonium persulfate (polymerization initiator) was added to the separable flask.

  Next, 55.0 parts by mass of ion-exchanged water and 108 parts by mass of the first emulsified dispersion were collectively added to the separable flask. As the first emulsion dispersion, an aqueous solution of 36.0 parts by mass of tetramethylolpropane triacrylate (having a solubility in water (25 ° C.) of 1% by mass or less) and 20.0 parts by mass of sodium dodecylbenzenesulfonate ( An emulsion dispersion was used which was obtained by emulsifying a concentration of 15% by mass with a homogenizer ("UltraTarax T50" manufactured by IKA Corporation). Thereafter, the temperature in the separable flask was kept at 70 ° C. for 3 hours. While maintaining the temperature in the separable flask at 70 ° C., the contents of the separable flask were polymerized.

  Subsequently, using the dropping funnel, 126 parts by mass of ion exchange water and 240 parts by mass of the second emulsified dispersion were dropped to the separable flask. As a second emulsion dispersion, 69.0 parts by mass of trimethylolpropane triacrylate (the solubility (25 ° C. in water) is 1% by mass or less), 30.0 parts by mass of ethylene glycol dimethacrylate and 15.0 parts by mass An emulsified dispersion was used which was obtained by emulsifying an aqueous solution (concentration: 8% by mass) of a mass part of sodium dodecylbenzene sulfonate with a homogenizer ("Ultratarax T50" manufactured by IKA Corporation). The dropping speed was 1 g / min, and dropping was finished after about 4 hours. Thereafter, the temperature in the separable flask was kept at 70 ° C. for 2 hours. While maintaining the temperature in the separable flask at 70 ° C., the contents of the separable flask were polymerized to obtain an emulsion of fine particles composed of an acrylic resin. Using a lyophilizer, the obtained emulsion of resin fine particles (fine particles made of an acrylic resin) was freeze-dried. Thereafter, the particle size of the resin fine particles was made uniform using an air classifier, and then the resin fine particles were sieved using a 2400 mesh (opening 5 μm) sieve. Thus, a powder containing a plurality of resin fine particles I was obtained.

[Method for measuring the number average primary particle diameter of resin fine particles]
The number average primary particle size of the resin fine particles was determined according to the following method. First, a SEM photograph of resin fine particles was taken using a scanning electron microscope. Images of 50 resin fine particles were randomly extracted from the obtained SEM photograph. Using the extracted image of the resin fine particles, the length of the resin fine particles in the major axis direction was determined. The total of the determined lengths was divided by the number of resin fine particles (specifically, 50). The obtained value was defined as the number average primary particle size of the resin fine particles. The results are shown in Table 2.

[Toner Production Method]
(Method of Manufacturing Toner T-1)
First, toner mother particles were prepared. 39. Specifically, 48.0 parts by mass of a first polyester resin (mass average molecular weight: 300000, glass transition point: 65 ° C.) using an FM mixer (“FM-10” manufactured by Japan Coke Industry Co., Ltd.), 39. 0 parts by mass of a second polyester resin (mass average molecular weight: 75000, glass transition point: 61 ° C.), 8.00 parts by mass of carbon black (“MA100” manufactured by Mitsubishi Chemical Corporation), and 2.00 parts by mass of Charge control agent ("BONTRON (registered trademark) N-71" manufactured by Orient Chemical Industry Co., Ltd.) and 3.00 parts by mass of a release agent ("Nissan Elector (registered trademark) WEP-5" manufactured by NOF Corporation) Ingredient: Pentaerythritol behenate ester wax, melting temperature: 84 ° C.).

The obtained mixture was melt-kneaded using a twin-screw extruder ("TEM-26SS" manufactured by Toshiba Machine Co., Ltd.). Thereafter, the obtained kneaded material was cooled. The cooled kneaded product was coarsely pulverized with a set particle diameter of 2 mm using a pulverizer (“ROTOPLEX 16/8 type” manufactured by Toa Instruments Co., Ltd.). The obtained coarsely pulverized material was finely pulverized using a pulverizer ("Turbomill RS type" manufactured by Freund Turbo Co., Ltd.). The obtained finely pulverized product was classified using a classifier (“Elbow Jet EJ-LABO type” manufactured by Nippon Steel Mining Co., Ltd.). As a result, toner base particles having a volume median diameter (D ₅₀ ) of 7.0 μm were obtained.

  An external additive was externally added to the obtained toner base particles. Specifically, 100 parts by mass of toner base particles and 1.50 parts by mass of positively chargeable silica particles (rotation speed of 3500 rpm using an FM mixer ("FM-10" manufactured by Nippon Coke Industry Co., Ltd.)) Dry silica particles imparted with positive charge by surface treatment, “AEROSIL (registered trademark) REA200” manufactured by Nippon Aerosil Co., Ltd., number average primary particle size: 13 nm, and 1.00 parts by mass of titanium oxide particles (Taika Co., Ltd.) Contents: untreated titanium oxide fine particles, number average primary particle diameter: 35 nm, and 1.00 parts by mass of resin fine particles A were mixed for 5 minutes. As a result, positively chargeable silica particles, titanium oxide particles, and resin fine particles A adhered to the surface of the toner base particles. Then, sieving was performed using a 300 mesh sieve (aperture 48 μm). As a result, Toner T-1 containing a large number of toner particles was obtained.

(Manufacturing method of toners T-2 to T-9)
Toners T-2 to T-9 were obtained in accordance with the production method of the toner T-1, except that the resin fine particles B to I shown in Table 2 were used as the resin fine particles.

[Carrier manufacturing method]
(Method of Manufacturing Carrier C-1)
As a carrier core, a Mn-Mg-Sr ferrite core ("EF-35" manufactured by Powder Tech Co., Ltd., particle diameter 35 μm) was prepared.

  Next, the carrier coat layer a was formed on the surface of the carrier core. Specifically, the phenol resin was dissolved in methyl ethyl ketone to obtain a coating solution. A powder containing a plurality of resin fine particles A was used as the phenol resin. The obtained coating liquid was sprayed on the carrier core. Thereby, the coating film containing a coating liquid was provided on the surface of the carrier core. The carrier core provided with the coating film on the surface was heated at 200 ° C. for 1 hour. Agglomerates were removed from the obtained powder using a 200 mesh sieve (aperture 73 μm). As a result, carrier C-1 including a large number of carrier particles was obtained.

(Method for producing carriers C-2 to C-5)
Carriers C-2 to C-5 were obtained according to the method for producing carrier C-1, except that the resins listed in Table 3 were used instead of the phenol resin. In addition, as the epoxy resin, a powder containing a plurality of resin fine particles F was used. As the silicone resin, a powder containing a plurality of resin fine particles G was used. A powder containing a plurality of resin fine particles H was used as the melamine resin. A powder containing a plurality of resin particles I was used as the acrylic resin.

(Method of manufacturing Carrier C-6)
A polyester resin (Nippon Synthetic Chemical Industry Co., Ltd. “polyester resin TP-220”) was dissolved in methyl ethyl ketone to obtain a coating solution. The obtained coating liquid was sprayed on the carrier core prepared at the time of manufacture of the carrier C-1. Thereby, the coating film containing a coating liquid was provided on the surface of the carrier core. The carrier core provided with the coating on the surface was vacuum dried at 40 ° C. Agglomerates were removed from the obtained powder using a 200 mesh sieve (aperture 73 μm). As a result, Carrier C-6 containing a large number of carrier particles was obtained.

(Method of Manufacturing Carrier C-7)
Carrier C-7 was produced without forming a carrier coat layer. That is, carrier C-7 contained many Mn-Mg-Sr ferrite core (carrier core prepared at the time of manufacture of carrier C-1).

[Method of measuring thickness of carrier coat layer]
The thickness of the carrier coat layer was determined according to the following method. First, using a scanning electron microscope, an SEM photograph of the carrier core before forming the carrier coat layer was taken. Images of 50 carrier cores were randomly extracted from the obtained SEM photograph. Using the extracted image of the carrier core, the length of the carrier core in the major axis direction was obtained. The total of the determined lengths was divided by the number of carrier cores (specifically, 50). The obtained value was taken as the number average primary particle diameter of the carrier core.

Next, using a scanning electron microscope, an SEM photograph of carrier particles (having a carrier coat layer formed on the surface of the carrier core) was taken. Images of 50 carrier particles were randomly extracted from the obtained SEM photograph. Using the extracted image of the carrier particles, the length of each carrier particle in the major axis direction was determined. The total of the determined lengths was divided by the number of carrier particles (specifically, 50). The obtained value was taken as the number average primary particle diameter of carrier particles. And the thickness of the carrier coat layer was calculated | required using the following formula.
(Thickness of carrier coat layer) = [(number average primary particle diameter of carrier particles)-(number average primary particle diameter of carrier core)] / 2

[Confirmation of coating state of carrier coat layer]
According to the method shown below, the coating state of the carrier coat layer on the surface of the carrier core was confirmed. First, using a scanning electron microscope, an SEM photograph of carrier particles (having a carrier coat layer formed on the surface of a carrier core) was taken. The covering state of the carrier coat layer on the surface of the carrier core was visually confirmed using the obtained SEM photograph. And it confirmed that the carrier coat layer was formed in the whole surface of a carrier core in the carrier particle contained in each of carriers C-1 to C-6. That is, it was confirmed that in the carrier particles contained in each of the carriers C-1 to C-6, the coverage of the carrier coat layer on the surface of the carrier core was 100%.

[Method for producing two-component developer]
(Method for producing two-component developer D-1)
10.0 parts by mass of toner T-1 and 100 parts by mass of carrier C-1 using a rocking mixer ("rocking mixer (registered trademark)" manufactured by Aichi Electric Co., Ltd., mixing method: container rotation rocking method) Was mixed for 30 minutes. In this way, a two-component developer D-1 was obtained.

(Method for producing two-component developers D-2 to D-16)
Two-component developers D-2 to D-16 were produced according to the production method of the two-component developer D-1, except that the toner and carrier shown in Table 1 were used.

[Evaluation method]
The two-component developers D-1 to D-16 were evaluated according to the following method. As the target device, a color multifunction peripheral (“FS-C5250DN” manufactured by Kyocera Document Solutions Inc.) was used. As target samples, each of two-component developers D-1 to D-16 was used.

(Measurement of toner charge)
First, after placing the target sample in the housing portion of the developing device of the target device, the charge amount (initial) of the toner was measured. Next, 100,000 sample images with a printing rate of 5% were continuously printed in an environment of a temperature of 23 ° C. and a humidity of 50% RH. Thereafter, the charge amount of the toner (after printing durability) was measured.

The charge amount of toner (initial) and the charge amount of toner (after printing) were measured according to the method described below. Specifically, a target sample of 0.10 ± 0.01 g was taken out from the housing of the developing device of the target device and placed in a measurement cell of a Q / m meter (“MODEL 210HS” manufactured by Trek). Only the toner of the target sample placed in the measurement cell was sucked through a sieve (known mass) for 10 seconds. The total amount of electricity of the sucked toner was measured using the above Q / m meter. In addition, the mass of the sieve before suction and the mass of the sieve after suction were measured using an electronic balance. The mass of the toner sucked was calculated by subtracting the mass of the sieve before suction from the mass of the sieve after suction. Then, the charge amount (μC / g) of the toner was calculated using the following equation.
[Charge amount of toner (μC / g)] = [Total electric amount of attracted toner (μC)] / [Mass of attracted toner (g)]

  If each of the toner charge amount (initial) and the toner charge amount (after printing resistance) is 12 μC / g or more, it was evaluated as good. If each of the toner charge amount (initial) and the toner charge amount (after printing resistance) was less than 12 μC / g, it was evaluated as bad. The results are shown in Table 4.

(Measurement of image density)
First, the target sample was put in the accommodating portion of the developing device of the target device. Thereafter, a sample image including a solid image portion was printed on a printing paper. The reflection density (ID: image density) of the solid image portion of the printed paper after printing was measured using a reflection densitometer (“SpectroEye (registered trademark)” manufactured by X-Rite). In this way, the image density (initial) was measured.

  Next, 100,000 sample images with a printing rate of 5% were continuously printed in an environment of a temperature of 23 ° C. and a humidity of 50% RH. Thereafter, a sample image including a solid image portion was printed on a printing sheet. Using a reflection densitometer (“SpectroEye” manufactured by X-Rite), the reflection density (ID: image density) of the solid image portion of the printed paper after printing was measured. Thus, the image density (after printing endurance) was measured.

  When each of the image density (initial) and the image density (after printing) was 1.2 or more, it was evaluated as good. If each of the image density (initial) and the image density (after printing) was 1.1 or more and less than 1.2, it was evaluated as normal. If each of the image density (initial) and the image density (after printing) was less than 1.1, it was evaluated as bad. The results are shown in Table 4.

(Presence or absence of resin fine particles adhering to the surface of carrier particles)
First, after the target sample was placed in the housing portion of the developing device of the target device, it was confirmed whether resin fine particles were adhering to the surface of the carrier particles. Next, 100,000 sample images with a printing rate of 5% were continuously printed in an environment of a temperature of 23 ° C. and a humidity of 50% RH. Thereafter, it was confirmed whether or not resin fine particles were adhered to the surface of the carrier particles.

  According to the method described below, it was confirmed whether resin fine particles were adhered to the surface of the carrier particles. Specifically, the target sample was taken out of the housing of the developing device of the target device, and the carrier particles were taken out of the target sample taken out. The removed carrier particles were observed using a scanning electron microscope, and it was visually confirmed whether resin fine particles were attached to the surface of the carrier particles.

  If adhesion of resin fine particles was not confirmed at all on the surface of the carrier particles, it was evaluated as good (◯). If adhesion of a small amount of resin fine particles was confirmed on the surface of the carrier particles, it was evaluated as normal (Δ). When adhesion of a large amount of resin fine particles was confirmed on the surface of the carrier particles, it was evaluated as bad (x). The results are shown in Table 4.

[Evaluation results]
Table 4 shows the evaluation results of the two-component developers D-1 to D-16. Table 4 shows the toner charge amount (initial, after printing), image density (initial, after printing), and the presence or absence of resin fine particles on the surface of carrier particles (initial, after printing). The evaluation results are shown. In Table 4, numerical values represent measurement results. Further, the developer means a two-component developer. In the adhesion, the evaluation result of the presence or absence of adhesion of the resin fine particles on the surface of the carrier particle is described.

  Each of the two-component developers D-1 to D-5 (two-component developers according to Examples 1 to 5) includes a toner and a carrier that charges the toner by friction. The toner contained a plurality of toner particles having toner mother particles and a plurality of external additive particles each attached to the surface of the toner mother particles. The carrier contained a plurality of carrier particles having a carrier core and a carrier coat layer covering the surface of the carrier core. The external additive particles contained a plurality of first external additive particles having a number average primary particle diameter of 50 nm or more and 150 nm or less. The first external additive particles and the carrier coat layer each contained a first resin. The first resin was a phenol resin, an epoxy resin, or a silicone resin.

  As shown in Table 4, each of the two-component developers D-1 to D-5 was excellent in the toner charge amount and the image density even after printing. In the two-component developers D-1 to D-5, no adhesion of resin fine particles on the surface of the carrier particles was confirmed even after printing.

  On the other hand, in the two-component developer D-6 (two-component developer according to Comparative Example 1), the charge amount of the toner decreased and the image density decreased after printing. Further, after printing, a small amount of resin fine particles were confirmed to adhere to the surface of the carrier particles. As a reason for obtaining such a result, it is considered that the number average primary particle diameter of the resin fine particles is less than 50 nm. Specifically, if the number average primary particle diameter of the resin fine particles is less than 50 nm, the resin fine particles are easily embedded in the toner base particles as the number of printed sheets increases. Therefore, the resin fine particles hardly function as a spacer, and titanium oxide particles or positively chargeable silica particles (hereinafter, described as external additive particles different from the resin fine particles) easily come in contact with the surface of the carrier coat layer. As a result, external additive particles different from the resin fine particles are easily attached or buried on the surface of the carrier coat layer, and thus the toner base particles are attached or buried on the surface of the carrier particles together with the external additive particles different from the resin fine particles. It will be easier. Therefore, after printing, the charge amount of the toner decreased, the image density decreased, and adhesion of a small amount of resin fine particles was confirmed on the surface of the carrier particles.

  In the two-component developer D-7 (two-component developer according to Comparative Example 2), the charge amount of the toner decreased and the image density decreased after printing. Also, in the initial stage, adhesion of a large amount of resin fine particles was confirmed on the surface of the carrier particles. As a reason for obtaining such a result, it is considered that the number average primary particle diameter of the resin fine particles is more than 150 nm. Specifically, when the number average primary particle diameter of the resin fine particles is more than 150 nm, the resin fine particles are easily detached from the surface of the toner base particles even in the initial stage. Therefore, adhesion of a large amount of resin fine particles was confirmed on the surface of the carrier particles also in the initial stage.

  Further, when the number average primary particle diameter of the resin fine particles is more than 150 nm, as the number of printed sheets increases, detachment of the resin fine particles from the surface of the toner base particles is more likely to occur. Therefore, it becomes difficult for the resin fine particles to function as a spacer. Therefore, for the same reason as the two-component developer D-6, the charge amount of the toner decreased and the image density decreased after printing.

  In the two-component developer D-8 (the two-component developer according to Comparative Example 3), the charge amount of the toner was reduced after printing, and the image density was significantly reduced. Also, in the initial stage, adhesion of a small amount of resin fine particles was confirmed on the surface of the carrier particles, and after printing, adhesion of a large amount of resin fine particles was confirmed on the surface of the carrier particles. The reason why such a result was obtained is that the resin constituting the resin fine particles was a melamine resin, whereas the resin constituting the carrier coat layer was a phenol resin. Specifically, both the melamine resin and the phenol resin are thermosetting resins. However, melamine resin has positive chargeability, while phenol resin has negative chargeability. Therefore, since the resin fine particles and the carrier coat layer are charged to different polarities, the resin fine particles and the carrier coat layer electrically attract each other, and the resin fine particles are easily attached to or buried in the carrier coat layer. Therefore, the toner base particles are easily attached or buried in the carrier coat layer together with the resin fine particles, and the toner particles are easily attached or buried in the carrier coat layer. As a result, after printing, the charge amount of the toner decreased, the image density decreased remarkably, and a large amount of resin fine particles adhered to the surface of the carrier particles.

  In the two-component developer D-9 (the two-component developer according to Comparative Example 4), the charge amount of the toner was reduced and the image density was significantly reduced also in the initial stage. Also, in the initial stage, adhesion of a small amount of resin fine particles was confirmed on the surface of the carrier particles, and after printing, adhesion of a large amount of resin fine particles was confirmed on the surface of the carrier particles. As a reason for obtaining such a result, it can be considered that the resin constituting the carrier fine particles is a melamine resin while the resin constituting the resin fine particles is a phenol resin. Specifically, for the same reason as in the two-component developer D-8, after printing, the charge amount of the toner decreases, the image density significantly decreases, and adhesion of a large amount of resin fine particles is confirmed on the surface of the carrier particles. It was done. Further, since the carrier coat layer is composed of a resin having positive chargeability (specifically, a melamine resin), the toner is difficult to be positively charged. Therefore, even in the initial stage, the charge amount of the toner decreased and the image density significantly decreased.

  In the two-component developer D-10 (the two-component developer according to Comparative Example 5), the charge amount of the toner was reduced and the image density was reduced also in the initial stage. As a reason for obtaining such a result, it is considered that the resin constituting the resin fine particles and the resin constituting the carrier coat layer were respectively melamine resins. Specifically, since the carrier coat layer is made of a positively charged resin (specifically, a melamine resin), the toner is difficult to be positively charged. Therefore, even in the initial stage, the charge amount of the toner decreased and the image density decreased.

  In the two-component developers D-11 to D-14 (two-component developers according to Comparative Examples 6 to 9), the charge amount of the toner decreased and the image density decreased after printing. Further, after printing, a large amount of resin fine particles were confirmed to adhere to the surface of the carrier particles. The reason why such a result is obtained is that at least one of the resin constituting the resin fine particles and the resin constituting the carrier coat layer is a thermoplastic resin (specifically, an acrylic resin or a polyester resin). Is considered. Generally, the hardness of a thermoplastic resin is lower than the hardness of a thermosetting resin. Therefore, in the resin fine particle and the carrier coat layer, the hardness of one is lower than the hardness of the other, or the hardness of both is relatively low. As a result, the resin fine particles can not be prevented from adhering to or being buried in the carrier coat layer, and after printing, the charge amount of the toner decreases, the image density decreases, and a large amount of resin fine particles adhere to the surface of the carrier particles. Was confirmed.

  In the two-component developers D-15 to D-16 (two-component developers according to Comparative Examples 10 and 11), the charge amount of the toner was reduced and the image density was significantly reduced even in the initial stage. Further, after printing, a large amount of resin fine particles were confirmed to adhere to the surface of the carrier particles. The reason why such a result is obtained is considered that the toner is difficult to be charged because the surface of the carrier core is not coated with the carrier coat layer.

  The two-component developer according to the present invention can be used, for example, to form an image in a copying machine, a printer, or a multifunction machine.

10 toner particles 11 toner mother particles 13 external additive particles 15 first external additive particles 17 second external additive particles 20 carrier particles 21 carrier core 25 carrier coat layer 100 two-component developer

Claims (3)

A two-component developer comprising: an electrostatic latent image developing toner; and an electrostatic latent image developing carrier for charging the electrostatic latent image developing toner by friction,
The electrostatic latent image developing toner includes a plurality of toner particles each having a toner base particle and a plurality of external additive particles attached to the surface of the toner base particle,
The electrostatic latent image developing carrier includes a plurality of carrier particles having a carrier core and a carrier coat layer covering the surface of the carrier core,
The external additive particles include a plurality of first external additive particles having a number average primary particle diameter of 50 nm or more and 150 nm or less,
The first external additive particles and the carrier coat layer each contain a first resin,
Wherein the first resin is Ri phenolic resin, epoxy resin, or silicone resin der,
The external additive particles further include a plurality of second external additive particles having a number average primary particle diameter smaller than the first external additive particles,
The two- component developer, wherein the second external additive particles are positively charged silica particles .   The two-component developer according to claim 1, wherein a thickness of the carrier coat layer is 10 nm or more. A method for producing a two-component developer according to claim 1 or 2 , wherein
Producing the electrostatic latent image developing toner;
Producing the electrostatic latent image developing carrier;
Mixing the electrostatic latent image developing toner and the electrostatic latent image developing carrier,
The step of producing the electrostatic latent image developing toner includes the step of producing the first external additive particles containing the first resin,
The step of producing the electrostatic latent image developing carrier includes the step of forming the carrier coat layer on the surface of the carrier core,
The step of forming the carrier coat layer includes the step of providing a film containing the first solution on the surface of the carrier core,
A method of manufacturing a two-component developer, wherein the first solution contains the first external additive particles and a first solvent which dissolves the first external additive particles.

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